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The Pesticide Dilemma Chapter 23. What is a Pesticide? Pest - causes harm, nuisance “cide” to kill Homocide, insecticide, fungicide… Chemical killers.

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Presentation on theme: "The Pesticide Dilemma Chapter 23. What is a Pesticide? Pest - causes harm, nuisance “cide” to kill Homocide, insecticide, fungicide… Chemical killers."— Presentation transcript:

1 The Pesticide Dilemma Chapter 23

2 What is a Pesticide? Pest - causes harm, nuisance “cide” to kill Homocide, insecticide, fungicide… Chemical killers of pests

3 What is a Pesticide? First-Generation Pesticides Inorganic compounds (e.g., lead, mercury) Botanicals (e.g., nicotine, pyrethrin) Pyrethrin is derived from chrysanthemum flowers.

4 What is a Pesticide? Second-Generation Pesticides Synthetic botanicals (e.g., pyrethroids) DDT (organics)

5 Organic Molecules Hydrocarbons – backbone or ring of carbons with hydrogens – “ane” endings Meth Eth Prop But Pent Hex Hept Oct Non Dec Structure:

6 DDT DichloroDiphenylTrichloroEthane

7 What is a Pesticide? The Major Groups of Insecticides Chlorinated hydrocarbon (e.g., DDT) Organophosphates (e.g., malathion) Carbamates (e.g., carbaryl)

8 What is a Pesticide? The Major Kinds of Herbicides Selective herbicides (e.g., 2,4-D – kills broad-leaved plants) Nonselective herbicides (e.g., glyphosate, aka: Round-Up TM )

9 Benefits and Problems with Pesticides Benefit: Disease Control Location of malaria

10 Benefits and Problems with Pesticides Benefit: Crop production Farmers save ~$3 - $5 in crops for every $1 invested into pesticides Monoculture farming – large acreage of one crop

11 Benefits and Problems with Pesticides Problem: Evolution of Genetic Resistance # of species exhibiting genetic resistance to pesticides

12 Benefits and Problems with Pesticides Problem: Evolution of Genetic Resistance Creates a pesticide treadmill Pesticide application Kills most pests Resistant survive Numbers increase New population genetically resistant EVEN MORE INCREASE

13 Benefits and Problems with Pesticides Problem: Evolution of Genetic Resistance: Rachel Carson’s Silent Spring –Unofficial beginning of environmental movement (1962) Resistance Management: Create a “refuge” (no pesticide applied) Avoid repeated use of same pesticide

14 Benefits and Problems with Pesticides Problem: Imbalances in the Ecosystem Creation of New Pests

15 Benefits and Problems with Pesticides Problem: Persistence, Bioaccumulation, and Biological Magnification Biomagnification of DDT

16 Benefits and Problems with Pesticides Problem: Mobility in the Environment

17 Risks of Pesticides to Human Health Short-term Effects of Pesticides Handling of food with pesticide residue

18 Risks of Pesticides to Human Health Short-term Effects of Pesticides: Case-in-Point: The Bhopal Disaster 40 tons of methyl isocyanate gas released, India, December ,000 people exposed 2,500 immediately killed 2,500 more killed through time 50,000-60,000 have serious health problems

19 Risks of Pesticides to Human Health Long-term Effects of Pesticides: Potentially higher risk of cancer Sterility Miscarriage / birth defects Potentially higher risk for Parkinson’s disease

20 Alternatives to Pesticides Integrated Pest Management

21 Alternatives to Pesticides Using Cultivation Methods to Control Pests: Interplant mixtures of plants Strip cutting Planting, fertilizing, and irrigating at proper time Crop rotation Unique ways to catch/kill and keep pests away –Vaccuum cleaners –Deer examples

22 Alternatives to Pesticides Biological Controls: Naturally occurring diseases, parasites, or predators Pheromones and Hormones: Pheromones attract insects to traps Synthetic hormones induce abnormal development Reproductive Controls: Sterile-male technique – inundate pest population with large numbers of sterile males

23 Alternatives to Pesticides Genetic Controls: Using Genetically Modified plants (GMOs) Case-in-Point: Bt, Its Potential and Problems – bacterial insecticide Genetically modified corn to produce Bt toxin Potential problem: may affect non-target species, such as monarch butterfly Quarantine – customs inspections

24 Alternatives to Pesticides Integrated Pest Management Rice Production in Indonesia IPM introduced

25 Alternatives to Pesticides Irradiating Foods (and water) Predominantly used on meats Kills many microorganisms without chemicals

26 Laws Controlling Pesticide Use Food, Drug, and Cosmetics Act (1938) Pesticide Chemicals Amendment (1954) Delaney Cause (1958) - carcinogens Federal Insecticide, Fungicide, and Rodenticide Act (FIRFA) Estimates of Risk of Cancer from Pesticide Residue

27 Laws Controlling Pesticide Use Food, Drug, and Cosmetics Act (1938) Pesticide Chemicals (Miller) Amendment (1954) Delaney Cause (1958) Federal Insecticide, Fungicide, and Rodenticide Act (1947) Food Quality Protection Act (1996)

28 The Manufacture and Use of Banned Pesticides Some US companies still make banned or seriously restricted pesticides and export the product. This can potentially lead to the importation of food tainted with banned pesticides

29 The Manufacture and Use of Banned Pesticides The Global Ban of Persistent Organic Pollutants (POP’s)


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